Scripting the Action

At this point, your score should look exactly like this:

Before we start scripting, let's see how the movie runs
as-is. Hit the Rewind button directly underneath the Stage. Notice that
the playhead obediently jumps to the first frame. Making sure that the
Loop Playback button is selected (5 buttons to the right of the Rewind
button), hit the Play button below the Stage, and watch both the Stage and
Score for a little while and then press the Stop button below the
Stage. Annoying, no? What's happening is that the playhead is whipping
through the frames, returning to the beginning when it gets to the end and
then continuing. It hasn't been told otherwise. We'll soon address this
problem.

Double-click in the Script channel of Frame 1, directly above the 1
in the Score. A scripting pane will open that contains the code:

1 on exitFrame me
2
3 end

A blinking cursor will appear in the blank line 2, and at that
prompt enter "go to the frame" (without quotes), name the script "Hold",
which you do by entering the name in the blank field at the top of the
scripting window, and close the window. You'll see a new Cast member in
the Cast Window, and its number will appear in the scripting channel. So
what does that accomplish? It's telling Director that as the playhead
leaves frame 1 it should go to the frame its currently on. So the playhead
remains paused at that frame, waiting for further instructions.

A Simple Script. The Script window has menus that call up many lines of prefabricated code, making it easy to experiment.

Why "me"? You may have noticed the tiny word "me" in
line 1 of the above. That simply means "this frame". Though it doesn't
seem necessary, that's what the script says by default, so I figured I'd
just leave it alone.

We're going to need this exact script again, on frame 12, but
instead of typing it out again, just drag it from the Cast to the
Scripting channel of the score at frame 12.

Click in the gray area directly above the Scripting Channel for the
2nd frame. A triangle will appear with the text "New Marker". Replace that
text with the name "VidStart" (without quotes). Why are we doing this?
When we write the button scripts, we'll refer to this marker.

Tip: In a script, referring to specific frames is a
bad idea. What if you changed things around a bit and inserted media into
various frames of your movie? All the frame numbers would be wrong. You'd
have to change each and every script. If you use a marker, and you make
changes, you just move the marker; there's no need to touch your
scripts!

We're going to write one more short frame script before we script
the buttons. Double-click in the Script channel of the 2nd frame, the one
under the VidStart marker, and type the following script:

This script will ensure that whether a user presses Play for the first
time, or presses Play after pressing Pause, the video (actually both
videos) will continue playing right where they left off.

Scripting the Buttons

Click on the FullButton on the Score and then click the
Behavior tab on the Property Inspector. Click the plus-sign button to call
up the Behavior Popup and scroll to select New Behavior. Name the behavior
"Full View" and click OK. Click the scroll icon above the new behavior to
call up the Script Window; at the prompt, type the following code and
close the window:

1. on MouseUp me
2. set the blend of sprite(2) to 100
3. end MouseUp

Repeat Step 1 for the FeetButton, naming the new behavior "Feet
View". The script for Feet View is exactly the same as Full View, but line
2 of Feet View contains the code "set the blend of sprite(2) to 0"
(without quotes).

What we're doing here is making the video in Channel 2 transparent
(where the blend = 0) or opaque (where the blend = 100). So when a user
clicks the Feet View button, even though the video of the Full View is
transparent, they still hear the exact same audio, and since the two
videos begin and end at the same point relative to the music, the feet
keep time with the music from the other video.

Follow the same steps for PlayButton, PauseButton, and
RewindButton, naming the behaviors Play, Pause, and Rewind, and using the
following scripts for each:

What just happened? We told each of these buttons that after you click
on them (MouseUp) several things should happen to several sprites. The
MovieRate property says, "The video is playing (1)" or "The video is not
playing (0)." And the MovieTime property says "When the MovieTime is 0,
the video is at the beginning."

We're almost there. Click the Rewind button below the Stage and
then the Play button (also below the Stage). The movie will present the
first frame and then pause, waiting for input. Click the Play button in
your movie and watch both the stage and the score. The film plays from
beginning to end and then pauses at the final frame. However, the video
clip should play for about 30 seconds, and we're only getting about 5
seconds out of it. The problem is that the video has an independent timing
from that of the playhead. To get around this problem, add the following
script in the Script channel of frame 11, and name it Video Loop:

This is a very long-winded way of saying that if the video is over,
proceed to the next frame, but if the video is not over, that is, if "My
Movie's Time" is less than the duration of the video, then keep playing
the video. Lines 2 through 3 set up the variables that are calculated in
line 5. How did I, a non-programmer, come up with code such as this? I
copied it verbatim from Macromedia's Help file, substituting "sprite(2)"
for the sprite name. Because the navigation ensures that both movies will
always play simultaneously, I need only reference one of the videos, in
this case, the video playing in Channel 2.

All that remains is one little detail: the Replay button in frame
12. But because we want it to do the exact same thing as the Play button
in frames 1 through 11, we won't have to rewrite the script. Just select
the ReplayButton in the Score (12th frame, 2nd channel), hit the Behavior
pop-up button on the Property Inspector as you did before, but instead of
creating a new behavior, just scroll down and select Play.

Creating a Shockwave version of this file required a few extra
steps that go beyond the scope of this tutorial. But to create a
self-running version of the movie for distribution (a "projector"), choose
Create Projector from the file menu and follow the steps to create a
projector of your .dir file (to quit the projector, hit Command-Q). When
you distribute the projector, include copies of the QuickTime movies in
the same folder; these aren't included in the packaging process.

And with that, you're done. Hit Rewind and Play in the control strip
below the stage and then hit Play in the movie. Switch between Full View
and Feet View. Experiment with Pause, Rewind, and Replay. And now that
you've learned all there is to know about Samba, get up from the computer
and hit that dance floor!

David Weiss
is an Oakland, California based freelance writer. He's worked as
a senior editor at Macworld magazine, and as the lead editor of MacHome
Journal. Read more about David at www.davidweiss.net.